Can anyone please recommend a website or a book that covers calculating Poker Odds and Probabilities in detail. I know how to calculate pot odds | implied odds and whether or not I have the odds to call the raise etc. However, i find myself lost when I read other peoples comments that my 6c4c are x% fav/dog against XY hand.

I was reading Gus's book - every hand revealed and Gus is a very mathematically correct player apart from being a maniac - time n again he mentions that my hand was 30% fav against my opponents pre flop. HOw do you memorize, more over how do u find out what your opponent is holding? let alone find the percentage of ur hand being successful against your opponent.